A conventional horizontal type coke oven battery for manufacturing metallurgical coke comprises a plurality of coking ovens for carbonizing coal charge, a plurality of combustion chambers for burning fuel gas, a regenerator for storing remaining heat of the combustion waste gas from the combustion chambers, and a sole flue for directing the combustion waste gas after heat exchange in the regenerator to a stack. Said plurality of coking chambers and combustion chambers are alternately arranged in the horizontal direction on the regenerator. Each of the combustion chambers comprises a plurality of heating flues, where fuel gas is burnt to heat and carbonize coal charge in the coking ovens on the both sides of the coking chamber through the oven walls, and thus to manufacture coke. The sole flue is installed outside and below the regenerator on the both longitudinal sides thereof, or directly below the regenerator. above described structure is a very large-scale structure easily subjected to damage, built by piling up a large number of bricks. The foundation structure for such a coke oven battery should therefore, in the occurrence of earthquake, not only be capable of largely reducing the input acceleration of a seismic wave transmitted to the coke oven battery to minimize the maximum relative displacement, the residual displacement and the acceleration produced in the coke oven battery, but also permit smooth release of expansion and contraction moments of the coke oven battery under the effect of heat, thereby preventing damage to the coke oven battery caused by the input acceleration of a seismic wave and/or expansion and contraction under the effect of temperature change.
With this requirement in view, several earthquake-proof foundation structure for a horizontal type coke oven battery have been proposed. For example, Japanese Patent Publication No. 962/74 dated Jan. 10, 1974, which matured into Japanese Pat. No. 743,738, corresponding to West-German patent application No. P1708549.3 dated Jan. 22, 1968 discloses an earthquake-proof foundation structure for a horizontal type coke oven battery having a sole flue outside and below the regenerator on the both longitudinal sides, which comprises:
a base plate; a supporting plate for mounting thereon said horizontal type coke oven battery; a plurality of columnar supports arranged substantially in a vertical position in the space between said base plate and said supporting plate; a buffer for absorbing the input acceleration of a seismic wave in the longitudinal direction of the coke oven battery, provided near the middle of the longitudinal center line of said space (hereinafter referred to as the "longitudinal buffer"); and buffers for absorbing the input acceleration of a seismic wave in the transverse direction of the coke oven battery, provided in two sets each within the ranges of 1/4 from the both ends of said longitudinal center line (hereinafter referred to as the "transverse buffer"); said supporting plate being supported on said base plate by means of said plurality of supports; said horizontal type coke oven battery being mounted on said supporting plate; each of said plurality of supports being connected substantially in a vertical position to said supporting plate and said base plate, movably in any direction through a bearing at the head portion and the leg portion thereof; each of said longitudinal buffer and said transverse buffers comprising two opposite projections fixed to the upper surface of said base plate and a projection fixed to the lower surface of said supporting plate, said projection fixed to the lower surface of said supporting plate projecting into the space between said two projections fixed to the upper surface of said base plate, and an elastic body being provided in each of the gaps between said two projections fixed to the upper surface of said base plate and said projection fixed to the lower surface of said supporting plate.
In the earthquake-proof foundation structure having the aforementioned structure, the input acceleration of a seismic wave in all directions transmitted from the ground to the base plate is absorbed by the longitudinal buffer and/or the transverse buffers. It is therefore possible to largely reduce the input acceleration of a seismic wave transmitted to the coke oven battery mounted on the supporting plate and hence to prevent damage to the coke oven battery caused by an earthquake. The horizontal transverse force applied to the coke oven battery by a pusher is abosrbed by the transverse buffers. Furthermore, since the difference in expansion and contraction caused by a change in temperature between the base plate and the supporting plate is absorbed by the plurality of supports movable in all directions, no bending moment is produced between the base plate and the supporting plate.
In the above-mentioned earthquake-proof foundation structure, however, each of the plurality of supports is connected substantially in a vertical position to the supporting plate and the base plate, movably in all directions through a bearing at the head portion and the leg portion thereof. Therefore, when the input acceleration of a seismic wave produces a considerable relative displacement between the base plate and the supporting plate, and as a result, said pluraity of supports largely incline, there is a serious fear that said plurality of supports having thus inclined may not be able to withstand the load of the coke oven battery mounted on the supporting plate. The coke oven battery is mounted directly on the supporting plate without no sliding layer in between. Therefore, even if no bending moment is produced between the base plate and the supporting plate as mentioned above, a bending moment caused by a change in temperature may be produced between the supporting plate and the lower surface of the coke oven battery.
An earthquake-proof foundation structure for a horizontal type coke oven battery having a sole flue directly below the regenerator, as shown in the schematic transverse vertical section view given in FIG. 1 has been proposed, which is the most pertinent to the present invention.
In FIG. 1, 1' are a plurality of foundation piles driven substantially vertically into the ground; 2' is a pile plate comprising solid concrete, rigidly connected substantially in a horizontal position to the tops of said plurality of foundation piles 1'; 3' is a base plate comprising solid concrete for mounting thereon a horizontal type coke oven battery described later, said base plate 3' being placed substantially in a horizontal position on said pile plate 2' through a sliding layer 6'; and 4' is a horizontal type coke oven battery comprising a regenerator 4a', a plurality of coking ovens and combustion chambers 4b' alternately arranged in the horizontal direction on said regenerator 4a', and a sole flue 5' installed directly below said regenerator 4a'. Said coke oven battery 4' is mounted on said base plate 3' through a sliding layer 7'. Each of the sliding layers 6' and 7' is formed by tightly laying a plurality of about 1-mm thick steel sheets coated with graphite grease over the entire surface thereof into two or three laminations. However, among the surfaces of said plurality of steel sheets, those being in contact with the upper surface of the pile plate 2', the lower surface of the base plate 3', the upper surface of the base plate 3' and the lower surface of the bottom 5a' of the sole flue 5' of the coke oven battery 4' are not coated with graphite grease. Said plurality of steel sheets may have any dimensions, and said plurality of steel sheets are tightly laid into two or three laminations by bringing their end edges into butt contact so that there may be neither gap nor overlap between their end edges. Incidentally, 17' is a heat-insulation layer comprising refractory, which covers the upper surface of the base plate 3'.
According to the earthquake-proof foundation structure shown in FIG. 1 comprising the foundation piles 1', the pile plate 2', the base plate 3' and the sliding layers 6' and 7', the input acceleration of a seismic wave transmitted to the coke oven battery 4' is reduced by the sliding layers 6' and 7', thus permitting prevention of a damage to the coke oven battery 4' caused by an earthquake. It is also possible, under the effect of the sliding layer 7', to smoothly release expansion and contraction moments caused by a change in temperature of the bottom 5a' of the sole flue 5' of the coke oven battery 4'.
The theory regarding such an earthquake-proof effect of the foundation structure shown in FIG. 1 is based on the following fundamental concept. More specifically, the sliding layers 6' and 7' are considered to have a frictional coefficient of 0.2 as the design value. Therefore, when the input acceleration of a seismic wave is transmitted through the ground, the foundation piles 1', the pile plate 2', the sliding layer 6', the base plate 3' and the sliding layer 7' to the coke oven battery 4', the acceleration produced in the coke oven battery 4' is not considered to exceed 200 gal corresponding to the frictional coefficient of 0.2 as shown in the following equation:
Gravitational acceleration "g"=980 cm/s.sup.2 EQU g.times.0.2=980 cm/s.sup.2 .times.0.2=196 gal.apprxeq.200 gal
Therefore, in the case where the input acceleration of a seismic wave transmitted to the pile plate 2' through the foundation pile 1 ' is up to 200 gal, there occurs no relative displacement among the pile plate 2', the base plate 3' and the coke oven battery 4', these moving as an integral body by the friction, and thus, no adverse effect of earthquake exerts on the coke oven battery 4'. On the other hand, in the case where the input acceleration of a seismic wave transmitted to the pile plate 2' through the foundation pile 1' is over 200 gal, only the pile plate 2' moves in a behavior corresponding to the seismic wave under the effect of the sliding layers 6' and 7', and the base plate 3' and the coke oven battery 4' are kept in the stationary state. In an earthquake of any magnitude, therefore, it has been considered that no residual displacement would be produced among the pile plate 2', the base plate 3' and the coke oven battery 4'.
According to the aforementioned fundamental concept concerning the earthquake-proof effect of the foundation structure shown in FIG. 1, if the frictional coefficient of the sliding layers 6' and 7' is close to zero, almost no input acceleration of a seismic wave would be transmitted to the coke oven battery 4', and in an earthquake of any magnitude, the coke oven battery 4' would be kept in the ideal stationary state. We have however noticed that there are the following serious doubts in the conventional fundamental concept regarding the earthquake-proof effect mentioned above:
(1) It is doubtful whether or not the graphite grease of the sliding layers 6' and 7' have actually a frictional coefficient of 0.2 just as designed;
(2) the frictional mechanism of the sliding layers 6' and 7' including graphite grease is presumed to include not only a simple static friction, but also a viscous friction;
(3) because the sliding layers 6' and 7' have no function to inhibit inertia force produced in the coke oven battery 4' in an earthquake, the coke oven battery 4' is placed in an unstable state at the time of earthquake. Depending upon the magnitude of the earthquake, therefore, considerable relative displacement and residual displacement may be produced in the coke oven battery 4'.